A nosecap for a gas turbine engine is schematically illustrated in FIG. 1 and indicated generally at 10. In a gas turbine engine, the nosecap 10 is disposed in the flowpath forward of the engine spinner cone and is bolted to the spinner cone through a plurality of bolt holes 12. The bolts (not shown) are oriented axially and are recessed from the flowpath in bolt pockets 14 near the aft edge of the nosecap 10. Each bolt pocket 14 includes a leading edge wall 15, a trailing edge wall 16, and a transition area wall 17 disposed between the leading edge wall 15 and the trailing edge wall 16. The transition area wall 17 is disposed at a fixed radius from a center of the bolt hole 12. The leading edge wall 15 and the trailing edge wall 16 comprise straight wall segments extending from the transition area wall 17. The bolt pocket 14 of the nosecap 10 is symmetric about a plane 19 passing through the geometric center 18 of the nosecap 10 and passing through and dividing the bolt hole 12. Most nosecaps 10 are formed from a poly-paraphenylene terephthalamide (such as that sold under the brand Kevlar®) and fiberglass two-dimensional laminate construction with a fluoroelastomer erosion coating.
Nosecaps 10 are designed to resist erosion and withstand hail strike without sustaining damage or experiencing large deflections. During medium and large birdstrike events, the nosecap 10 typically liberates and is considered frangible. It is ingested into the fan of the engine and expelled from the exhaust of the engine, causing no downstream economic damage.
The nosecap 10 is expensive due to the manual labor required in the nosecap 10 construction layup process and the raw material cost. Additionally, the nosecap 10 geometry is somewhat limited by the manufacturing process which, for example, requires large, smooth radii and gentle changes in part curvature.
The nosecap 10 exhibits erosion damage on the trailing edge wall 16 of the bolt pocket 14. This surface receives particle impact velocity that is the vector sum of the aircraft velocity and the rotational velocity of the nosecap 10 at that radius. Erosion at this location is typically worse than any other location on the nosecap 10.
Therefore, improvements in gas turbine engine nosecaps are still needed in the art.